Due to increased competition and eroding revenue margins, service providers are demanding better yields from their network infrastructure. Thus, bandwidth-on-demand for event driven traffic, or creation of bandwidth brokering services are just a few of the new optical layer services that can be created. Attributes such as protection level, latency, priority, transparency, and diversity may also be used to define optical services. These need to be either general characteristics of the network or specific characteristics of a connection. As such, class of service (CoS) considerations need to be taken into account both when planning a network, when routing an individual connection, and when collecting the revenue.
These demands have exposed a number of weaknesses with respect to the current optical networks and their mode of operation.
Traditional WDM (wavelength division multiplexed) network has a point-to-point configuration, with electrical cross-connects (EXC) provided at all switching nodes. This network architecture allows fairly limited optical layer service offerings and is also very difficult to scale. Thus, a point-to-point architecture does not have the ability to turn up/down bandwidth rapidly, or/and to provide bandwidth optimized for the data layer needs, even if the equipment for the new service is in place.
As a result, there is a trend to transit from the point-to-point configurations to a new architecture, where the connections are routed, switched and monitored independently. To enable automatic or ‘point-and-click’, dynamic connection set-up and removal, the network management must avail itself with a very accurate inventory of all current network resources at a finer granularity (i.e. at the optical module level) than in current networks. This information must also include the real-time allocation of the network resources to the currently active connections. Furthermore, in this type of network, the traditional manual span-by-span engineering cannot be performed as the channels sharing the same fiber do not have the same origin, destination and network traversing history. Rather, the network management must be provided with automatic end-to-end optical path engineering, which requires availability of large amount of performance and topology data. Thus, the network management must keep an updated view of the actual and estimated optical performance for all optical spans, links, paths in the context of connections being set-up and torn down arbitrarily.
In short, the network management of an agile optical network needs to be provided with a means to collect, update, and maintain topology and performance information and with the ability to fast retrieve it when needed. This in turn implies changes in the type and granularity of the network data that is kept, and also in the way this data is organized.